This invention relates to electronic devices with antennas, and more particularly, to electronic devices with sensors for determining antenna position.
It may be desirable to include wireless communications capabilities in an electronic device. Electronic devices may use wireless communications to communicate with wireless base stations. For example, electronic devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz and the Bluetooth® band at 2.4 GHz. Electronic devices may also use other types of communications links. For example, electronic devices may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Communications are also possible in data service bands such as the 3G data communications band at 2100 MHz (commonly referred to as UMTS or Universal Mobile Telecommunications System).
Many popular housing materials such as metal have a high conductivity. This poses challenges when designing an antenna for an electronic device with this type of housing. An internal antenna would be shielded by a high-conductivity housing, so internal antenna designs are often not considered practical in electronic devices with conductive cases. On the other hand, external antenna designs that protrude permanently from a device's housing may have an unattractive appearance. Permanently extended external antenna designs may also be susceptible to damage.
Retractable (extendable) antennas may be used to improve the visual appearance of an electronic device and may to reduce the likelihood of antenna damage. However, it may not be suitable to operate this type of antenna when the antenna is in its retracted position. Operation of a retractable antenna in its stowed position may cause circuit damage or may lead to unwanted power losses.
It would therefore be desirable to be able to determine the position of an antenna in an electronic device.